<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="/demo/jquery-3.2.1.min.js"></script>
    <script src="/demo/bootstrap.min.js"></script>

    <!-- Bootstrap -->
    <link href="/demo/bootstrap.min.css" rel="stylesheet">
<style>
    /* 弹窗 */
    .modal {
        display: none; /* 默认隐藏 */
        position: fixed;
        z-index: 1;
        left: 0;
        top: 0;
        width: 100%;
        height: 100%;
        overflow: auto;
        background-color: rgb(0,0,0);
        background-color: rgba(0,0,0,0.4);
        -webkit-animation-name: fadeIn;
        -webkit-animation-duration: 0.4s;
        animation-name: fadeIn;
        animation-duration: 0.4s
    }

    /* 弹窗内容 */
    .modal-content {
        position: fixed;
        bottom: 0;
        background-color: #fefefe;
        width: 100%;
        -webkit-animation-name: slideIn;
        -webkit-animation-duration: 0.4s;
        animation-name: slideIn;
        animation-duration: 0.4s
    }

    /* 关闭按钮 */
    .close {
        color: white;
        float: right;
        font-size: 28px;
        font-weight: bold;
    }

    .close:hover,
    .close:focus {
        color: #000;
        text-decoration: none;
        cursor: pointer;
    }

    .modal-header {
        padding: 2px 16px;
        background-color: #5cb85c;
        color: white;
    }

    .modal-body {padding: 2px 16px;}

    .modal-footer {
        padding: 2px 16px;
        background-color: #5cb85c;
        color: white;
    }

    /* 添加动画 */
    @-webkit-keyframes slideIn {
        from {bottom: -300px; opacity: 0}
        to {bottom: 0; opacity: 1}
    }

    @keyframes slideIn {
        from {bottom: -300px; opacity: 0}
        to {bottom: 0; opacity: 1}
    }

    @-webkit-keyframes fadeIn {
        from {opacity: 0}
        to {opacity: 1}
    }

    @keyframes fadeIn {
        from {opacity: 0}
        to {opacity: 1}
    }
</style>
</head>
<script>
    // 获取弹窗
    var modal = document.getElementById('myModal');

    // 打开弹窗的按钮对象
    var btn = document.getElementById("myBtn");

    // 获取 <span> 元素，用于关闭弹窗 that closes the modal
    var span = document.getElementsByClassName("close")[0];

    // 点击按钮打开弹窗
    btn.onclick = function() {
        modal.style.display = "block";
    }

    // 点击 <span> (x), 关闭弹窗
    span.onclick = function() {
        modal.style.display = "none";
    }

    // 在用户点击其他地方时，关闭弹窗
    window.onclick = function(event) {
        if (event.target == modal) {
            modal.style.display = "none";
        }
    }
</script>

<body>
<!-- 打开弹窗按钮 -->
<button id="myBtn">打开弹窗</button>
<!-- 弹窗 -->
<div id="myModal" class="modal">

    <!-- 弹窗内容 -->
    <div class="modal-content">
        <div class="modal-header">
            <span class="close">&times;</span>
            <h2>弹窗头部</h2>
        </div>
        <div class="modal-body">
            <p>弹窗文本...</p>
            <p>弹窗文本...</p>
        </div>

    </div>
</div>
</body>
</html>